The desirability of providing dosage forms of biologically active substances which release the substance in a controlled manner and thus reduce the frequency of administration is well established.
Recent developments in the area of controlling the release of drugs include those disclosed in European Patent Application 81305426.9 and European Patent Application 82300416.3 which describe methods for controlling the release of drugs by microencapsulation and containment within a biodegradable matrix, respectively. U. Schroder J. Immunological Methods 70,127-132 (1984) and Biomaterials 5(2) 100-104 (1984) describes the fabrication and use of carbohydrate spheres as a crystalline slow release matrix for biologically active substances, where controlled release is obtained by erosion of the matrix. S. L. Davies et al, in The Journal of Dairy Science Vol. 66 No. 9, pp 1980-1981 (1983) describes a beeswax implant for administering growth hormone (oGH), while U.S. Pat. No. 4,452,775 describes a cholesterol matrix delivery system for sustained release of macromolecules including a variety of growth hormones.
The above references disclose a variety of solid matrix systems for the administration of biologically active substances. It is an object of the present invention to provide aqueous compositions of water dispersible and soluble polymers, and growth hormones, which are water soluble and are suitable for parenteral administration in aqueous medium. It is another object of this invention to provide a method for increasing and maintaining increased levels of growth hormones in the blood of treated animals and humans for extended periods of time and obtaining beneficial effects such as increasing weight gains and increasing milk production in lactating animals, by parenteral administration of the aqueous compositions of the invention.